Polishing head and polishing apparatus

Abstract

A polishing head capable of preventing contact between both side walls of an elastic membrane when a negative pressure is formed in a pressure chamber formed by the elastic membrane. The polishing head includes: a first elastic membrane configured to press the workpiece against the polishing pad; a retainer ring surrounding the first elastic membrane; a second elastic membrane configured to press the retainer ring against the polishing pad; a carrier to which the first elastic membrane is secured; and an attachment member arranged in a pressure chamber formed by the second elastic membrane and fixing the second elastic membrane to the carrier. The attachment member has a support portion extending toward the retainer ring along a side wall of the second elastic membrane.

What is claimed is: 
     
       1. A polishing head for pressing a workpiece against a polishing pad to polish the workpiece, comprising:
 a first elastic membrane configured to press the workpiece against the polishing pad; 
 a retainer ring surrounding the first elastic membrane; 
 a second elastic membrane configured to press the retainer ring against the polishing pad; 
 a carrier to which the first elastic membrane is secured; 
 an attachment member arranged in a pressure chamber formed by the second elastic membrane and fixing the second elastic membrane to the carrier; and 
 a coupling member configured to couple the second elastic membrane to the retainer ring, 
 the second elastic membrane including:
 a bottom wall coupled to the coupling member; and 
 a side wall coupled to the bottom wall, the attachment member having a support portion extending toward the retainer ring along the side wall, 
 
 wherein the attachment member has a groove extending along the support portion in a circumferential direction of the second elastic membrane. 
 
     
     
       2. The polishing head according to  claim 1 , wherein:
 the side wall comprises a first side wall and a second side wall separated from each other; 
 the support portion comprises two support portions extending along the first side wall and the second side wall, respectively; 
 the attachment member has a recessed portion located between the two support portions; and 
 the coupling member has a protruding portion which is housed in the recessed portion when the coupling member moves toward the attachment member. 
 
     
     
       3. The polishing head according to  claim 1 , wherein:
 the bottom wall has a cross-sectional shape curved toward the retainer ring; and 
 at least a part of the support portion is housed in the curved bottom wall when the coupling member moves toward the attachment member. 
 
     
     
       4. The polishing head according to  claim 1 , wherein at least an outer surface of the support portion has been subjected to a friction reduction treatment. 
     
     
       5. A polishing apparatus comprising:
 a polishing table configured to support a polishing pad; and 
 the polishing head according to  claim 1  for pressing the workpiece against the polishing pad to polish the workpiece. 
 
     
     
       6. A polishing head for pressing a workpiece against a polishing pad to polish the workpiece, comprising:
 a first elastic membrane configured to press the workpiece against the polishing pad; 
 a retainer ring surrounding the first elastic membrane; 
 a second elastic membrane configured to press the retainer ring against the polishing pad; 
 a carrier to which the first elastic membrane is secured; 
 an attachment member arranged in a pressure chamber formed by the second elastic membrane and fixing the second elastic membrane to the carrier; and 
 a coupling member configured to couple the second elastic membrane to the retainer ring, 
 the second elastic membrane including:
 a bottom wall coupled to the coupling member; and 
 a side wall coupled to the bottom wall, the attachment member having a support portion extending toward the retainer ring along the side wall, 
 
 wherein the attachment member has through-holes extending through the support portion, and the through-holes are arranged along a circumferential direction of the second elastic membrane. 
 
     
     
       7. The polishing head according to  claim 6 , wherein:
 the side wall comprises a first side wall and a second side wall separated from each other; 
 the support portion comprises two support portions extending along the first side wall and the second side wall, respectively; 
 the attachment member has a recessed portion located between the two support portions; and 
 the coupling member has a protruding portion which is housed in the recessed portion when the coupling member moves toward the attachment member. 
 
     
     
       8. The polishing head according to  claim 6 , wherein:
 the bottom wall has a cross-sectional shape curved toward the retainer ring; and 
 at least a part of the support portion is housed in the curved bottom wall when the coupling member moves toward the attachment member. 
 
     
     
       9. The polishing head according to  claim 6 , wherein at least an outer surface of the support portion has been subjected to a friction reduction treatment. 
     
     
       10. A polishing apparatus comprising:
 a polishing table configured to support a polishing pad; and 
 the polishing head according to  claim 6  for pressing the workpiece against the polishing pad to polish the workpiece.